Monofunctionally-blocked tris(2-hydroxyalkyl)isocyanurates and polyesters thereof

ABSTRACT

Monofunctionally-blocked tris(2-hydroxyalkyl)isocyanurates, made by reactionwith equimolar amount of a monocarboxylic acid, are statistically difunctional alcohols useful for making polyesters. Use of an Alpha -ethylenically unsaturated polycarboxylic acid or an Alpha -ethylenically unsaturated monocarboxylic acid blocking agent in conjunction with a cross-linking monomer gives casting resins which are heat resistant, self-extinguishing, weather resistant, and color stable.

United States Patent [151 3,683,048 Kolyer et al. [451 Aug. 8, 1972 [54]MONOFUNCTIONALLY-BLOCKED 3,235,553 2/1966 Sadle ..260/248 TRIS(2-3,331,839 7/1967 Little ..260/248 HYDROXYALKYDISQCYANURATES 3,407,20010/1968 Little et a1. ..260/248 A D p LYESTER T E F 3,477,996 11/1969Formani 260/75 N 0 S H REO 3,448,084 6/1969 Burdick et a1. ..260/75 [72]Inventors: John M. Kolyer, Convent; Albert A.

- Kveglis, Pine Brook, both of NJ O HER PUBLICATIONS [73] A i Alli d Chi l C ti N Goodman et al., Polyesters Vol. '1, New York 1965 York NY liL J t t d P l t El N Y k Filed: N 1970 183113,) lggz; ura e 0 yes ers,sevier, ew or 21 A 1. N 89,532 1 pp 0 Primary Examiner-Melvin GoldsteinRelated US. Application Data Attorney-Michael S. Jams: [63]Continuation-impart of Ser. No. 725,163, April 29, 1968, abandoned. [57]ABSTRACT I Monofunctionally-blocked tris(2-hydroxyalkyl)iso- 52 us. Cl...260/868, 260/40 R, 260/75 N, cyanurates, made y reactionwith equimolaramount 2 0 24 A of a monocarboxylic acid, are statistically difunctional[51] rm. c|......c0sr 21/00, CO8f2l/02, C08g 17/10 alcohol? useful formakmg p y of an [58] Field of Search ..260/75 N, 868 ethylemcallySaturated P ethylenically unsaturated monocarboxylic acid [56]References Cited blocking agent in conjunction with a cross-linkingmonomer gives casting resins which are heat resistant, UNlTED STATESPATENTS self-extinguishing, weather resistant, and color stable.3,215,758 1 l/ 1965 Hopkins ..260/868 15 Claims, No DrawingsMONOFUNCTIONALLY-BLOCKED TRIS(2- HYDROXYALKYLHSOCYANURATES ANDPOLYESTERS THEREOF RELATED APPLICATIONS BACKGROUND OF THE INVENTION Thisinvention relates to novel resinous compositions. Inparticular itrelates toblocked tris( 2-hydroxyalkyl-isocyanurates and polyestersderived therefrom.

Tris(2-hydroxyethyl)isocyanurate and polyesters derived therefrom areknown in the literature; for example, Little U.S. Pat. 3,088,948discloses tris(2- hydroXyethyDisocyanurate and its homologues, and MeyerU.S. Pat. 3,342,780 discloses polyesters derived from the isocyanurateand terephthalic and isophthalic acids. Also, Formaini application Ser.No. 443,655, filed Mar. 21, 1965, discloses the reaction of tris(2-hydroxyalkyl)isocyanurates with unsaturated acids such as maleic acid,to make polyesters. However, the prior art does not teach the beneficialeffect obtained by first blocking one hydroxyl group of a tris(2-hydroxyalkyl)isocyanurate prior to polyesterification.

SUMMARY OF THE INVENTION The novel materials of this invention arestatistically difunctional alcohols, i.e., monofunctionally-blockedtris-(2-hydroxyalkyl)isocyanurates, wherein each 2- hydroxyalkyl groupcontains from 2 to 4 carbon atoms, and polyesters derived therefrom.Tris( Z-hydroxyalkyl )isocyanurates are polyhydric alcohols of theformula:

wherein R is hydrogen, methyl or ethyl. By the termsmonofunctionally-blocked or simply blocked isocyanurate" as used in thisapplication, are meant those isocyanurates wherein one hydroxyl grouphas been esterified by reaction with about an equimolar amount of amonocarboxylic acid, thereby affording a statistically difunctionalalcohol. The blocked isocyanurateproducts of the invention have theformula:

wherein R is the residue of the blocking acid and R is as given above.

The blocked isocyanurates of this invention are useful in thepreparation of unsaturated polyesters by reaction with a polycarboxylicacid reactant. In particular, use of an a-ethylenically unsaturateddicarboxylic acid or derivative thereof or of an a-ethylenicallyunsaturated monocarboxylic blocking acid affords polyesters which canundergo cross-linking to afford casting resins of improved heatresistance, weatherability, color stability, self-extinguishingproperties and the like.

DETAILED DESCRIPTION OF THE INVENTION Tris(2-hydroxyethyl)isocyanurateis the preferred isocyanurate for the purposes of this invention, andits use will be described in detail hereinafter. This material isreadily prepared by methods taught in aforesaid U.S. Pat. No. 3,088,948.

The isocyanurate must be monofunctionally-blocked in the manner taughthereinafter, in order to obtain polyesters having the desiredproperties. If one of the isocyanurate hydroxyl groups is not blocked,the resulting polyester will. not, for example, have the desiredsolubility or gelation properties. Blocked tris(2-hydroxyethyl)isocyanurate, wherein one hydroxyl group is esterified,is prepared by conventional esterification processes, whereby the.isocyanurate is reacted with sutficient monocarboxylic acid to form astatistically difunctional alcohol viz. about an equimolar amount.

Suitable monocarboxylic blocking acids which can be used includealkanoic acids, preferably of 1-12 carbon atoms such as formic acid,acetic acid, propionic acid, butyric acid, pivalic acid, caproic acid,pelargonic acid and lauric acid. These acids can be unsubstituted orsubstituted with aryl, halogen or alkoxy groups, such as chloroaceticacid, B-bromopropionic acid, methoxyacetic acid, phenylacetic acid andthe like. Aromatic acids are also suitable blocking acids, includingbenzoic acid, alkylbenzoic acids such as 0-, m-- and p-toluic acids,halobenzoic acids such as 0-, mx and pchlorobenzoic acids or o-, mandp-bromobenzoic acids, nitrobenzoic acids, such as o-, m, andpnitrobenzoic acids and alkoxybenzoic acids such as anisic acid and thelike. The blocking acid can also contain an a-ethylenic unsaturatedgroup. Alkenoic acids containing up to about 12 carbon atoms, such asacrylic acid, methacrylic acid, crotonic acid and vinylacetic acid,either unsubstituted or substituted, can be used, particularly when itis desirable to use a saturated or aromatic dicarboxylic acid in thepreparation of polyesters.

About an equimolar amount of the monocarboxylic blocking acid willnormally be used i.e., between about 0.9 and 1.2 mols of monocarboxylicacid per mol of isocyanurate.

The reaction is preferably conducted under an inert atmosphere, forexample nitrogen, and either with or without a solvent. Solvents whichcan be used include the common inert solvents such as benzene, toluene,or xylene. The esterification is conducted at elevated temperatures forexample in the range of about to 230 C.; preferably the reaction will beconducted between 200 C. and 220 C.

No catalyst is necessary, although the usual esterification catalysts,such as p-toluenesulfonic acid, can be employed.

- The acid number of the reaction product provides a convenient measureto determine whether the esterification has proceeded far enough toprovide a monofunctionally-blocked isocyanurate. When this number, whichis the number of milligrams of potassium hydroxide required toneutralize one gram of the sample, has a value between about and 30, thedesired product has been obtained. When the acid number is greater than30, insufficient blocking has occurred and when it is less than about 5,excessive blocking has occurred. Preferably the blocked isocyanuratewill have an acid number of about 25-27. The acid number may bedetermined by standard procedures well known to those skilled in theart.

The blocked isocyanurate can be isolated if desired by standard recoveryprocedures such as solvent removal, extraction, crystallization, and thelike. Also it can be purified by recrystallization, trituration, etc.After isolation, the blocked isocyanurate can be subjected topolyesterification to afiord the desired polyesters.

The polyesters can also be obtained without isolation of the blockedisocyanurate, by adding a dicarboxylic acid and other polyesterificationingredients directly to the reaction mixture containing the blockedisocyanurate. This can be conveniently accomplished by lowering thetemperature of the reaction mixture to about 150 C., adding theadditional reactants and then raising the temperature t facilitatepolyesterification.

Dicarboxylic acids which can be used in the preparation of the instantunsaturated polyesters include free dicarboxylic acids, or derivativesthereof including their anhydrides, acyl halides, e.g. diacid chlorides,or lower dialkyl esters. Mixtures of functional dibasic acids can alsobe employed. a-Ethylenically unsaturated dicarboxylic acid reactantswhich can be used include maleic acid, maleic anhydride, fumaric acid,citraconic acid, mesoconic acid, tetrahydrophthalic acid, itaconicanhydride, endo-bis-S-norbomene-2,3- dicarboxylic acid; and isomers ofmethyl bicyclo (2'2- l)heptene-2, 3-dicarboxylic acid. Maleic anhydrideis the preferred unsaturated acid reactant. Dicarboxylic acids which donot contain an a-ethylenic double bond can be used when themonocarboxylic acid blocking agent contains an a-ethylenic double bond.Mixtures of an a-ethylenically unsaturated polycarboxylic acid with anaromatic or saturated dicarboxylic acid can also be employed. Polyestersderived from such mixtures are particularly useful when the benefitsderived from each type are desired; for example, high rigidity andthermal stability are obtained by using a mixture of maleic anhydrideand a phthalic acid. Suitable aromatic and saturated dicarboxylic acidreactants include phthalic, isophthalic and terephthalic acids; succinicacid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acids andthe like. Of course, mixtures of dibasic acids can also be used, ratherthan a single acid; mixtures of aromatic or saturated anda-ethylenically unsaturated acids are particularly useful when thebenefits derived from each type are desired; for example, high rigidityand thermal stability are obtained by using a mixture of maleic andphthalic acids or anhydrides.

in making the unsaturated polyesters, at least about 95 equivalentpercent of hydroxyl material should be employed based on the amount ofacid used, and preferably an excess of between 100 and 120 equivalentpercent of hydroxyl material will be used. The amount of hydroxylmaterial employed is specified herein in terms of equivalents since thealcohol and acid react on an equivalent basis rather than on a molarbasis.

After addition of the dicarboxylic acid reactant, heating of thereaction mixture is continued at an elevated temperature between aboutC. and 250 C. and preferably between about 200 and 225 C., until thedesired acid number is obtained. Usually preferred products will have anacid number less than about 60, although higher acid numbers may bedesireable depending upon molecular weight and end use criteria. Toobtain polyesters especially useful for casting, an acid number betweenabout 10 and 25 is desirable, preferably between about 18 and 2 1.

While the blocked isocyanurate can be employed as the sole polyhydricalcohol reactant in the instant polyesters, it can also be replaced inpart by one or more other polyhydric alcohols. As little as about 5percent by weight of the total polyhydric alcohol can be blockedisocyanurate, but preferably at least about 20 percent by weight will beblocked isocyanurate. On an equivalent basis, preferably at least about5 percent of the total polyhydric alcohol content will be a blockedisocyanurate.

Modifying polyhydric alcohols which can be employed in this fashioninclude ethylene glycol, propylene glycol, glycerin, pentaerythritol,l,l,ltrimethylolethane, l, l l -trimethylolpropane, sorbitol, mannitol,dipentaerythritol, a,w-aliphatic hydrocarbon diols having 4 to 5 carbonatoms, e.g., butanediol-l ,4, pentanediol-l,5, butene-2-diol-l,4, andbutyne-2-diol- 1,4, and cyclic glycols, e.g., 2,2,4,4-tetramethyl-l, 3-cyclobutanediol, hydroquinone di-beta-hydroxyethyl ether and l,4-cyclohexanedimethanol.

When a modifying polyhydric alcohol is used, it can be added to thepolyesterification reaction mixture along with the other componentsaccording to procedures well known to those skilled in the art.Excellent results are also obtained when the dicarboxylic acid ispartially esterified with the blocked isocyanurate prior to furtheresterification with a modifying glycol.

The glycols which may be advantageously used in this latter two-stepprocess may vary widely. in general, they are the glycols conventionallyused in preparing polyesters, including alkylene glycols of the formulaHOROH wherein R is alkylene, generally of 2 to 10 carbon atoms, e.g.,ethylene, propylene, butylene, etc. Ether alcohols are also suitablesuch as diethylene glycol, and dipropylene glycol. Other suitablealcohols are well known, such as tripropylene glycol, triethyleneglycol, tetramethylene glycol, neopentyl glycol, 2-methyl-1,3-pentanediol, l ,5 -pentanediol, hexamethylene glycol, etc.Preferably an alkylenediol will be used.

Inasmuch as an a-ethylenically unsaturated dicarboxylic acid ormonocarboxylic blocking group is employed in the polyesterificationreaction, it is desirable to add a vinyl polymerization inhibitor intothe reaction mixture, for example hydroquinone,mono-t-butylhydroquinone, benzoquinone and the like. Between about 0.02percent and 0.05 percent by weight of the inhibitor should be added.

The polyester can be isolated from the reaction mixture by a variety ofprocedures well known to those skilled in the art, for example byremoval of solvent, by cooling to afford solidification, etc.

In addition to the two-step procedure described hereinabove, wherein theblocked isocyanurate is first prepared and then polyesterified, it isalso possible to use a single-step process. For this purpose thepolycarboxylic acid reactant is added to the isocyanurate along with themonocarboxylic blocking agent. Depending upon the relative activities ofthe blocking agent and the polycarboxylic acid reactant, reactionconditions such as the reaction temperature, catalysts, order ofaddition of the reactants and the like can be adjusted to insure thatone hydroxyl group of the tris(2-hydroxyalkyl)-isocyanurate precursor isblocked by the monocarboxylic acid. In particular, provision must bemade for return of volatilized monocarboxylic acid to the reactionvessel.

Use of an a-unsaturated dicarboxylic acid in preparing polyesters fromblocked isocyanurates, or use of an isocyanurate blocked with analkenoic carboxylic acid, affords compositions suitable for laminates,casting resins, etc. For this purpose an appropriate cross-linkingmonomer is added to the composition, e.g., styrene, a-methylstyrene,methyl methacrylate, diallyl phthalate, triallylisocyanurate,triallylcyanurate, ethylene glycol dimethacrylate and homologs thereof,diethylene glycol divinyl ether, alkyl vinyl ethers, alkyl acrylates,etc.

The choice of cross-linking monomer will depend in part upon the desiredcharacteristics and properties of both the polyester and final productto be fabricated therefrom. For example, if it is desirable to use ahigh level of isocyanurate or unsaturated acid, etc. in preparingpolyester, in order to impart certain physical or chemical properties tothe product, the most advantageous monomer can vary from styrene to astyrene-methyl methacrylate mixture to diallyl phthalate. The selectionof cross-linking agent will be influenced in these instances byconsiderations such as solubility, shelf life of the compound, andproperties desired in the cured product, such as flame resistance,weatherability, and heat resistance.

The amount of cross-linking monomer employed will vary according to theend use of the product, but generally cross-linking monomerconcentrations between about 5 percent and 70 percent by weight of thetotal mixture will give products useful for casting and laminates.Preferably, the cross-linking monomer concentration will be between 30percent and 60 percent by weight of the total mixture.

In addition to the cross-linking monomer, unsaturated polyesters willalso contain a suitable vinyl polymerization initiator or catalyst forthe cross-linking, and optionally a promoter. lnitiators are well knownand include peroxides such as benzoyl peroxide, di-t-butyl peroxide,dicumene peroxide, methylethyl ketone peroxide and the like;hydroperoxides such as tbutylhydroperoxide; azo compounds such asazo-bisisobutyronitrile, azo-bis-valeronitrile and the like. Catalyticamounts of the initiator, e.g., 0.2-2 percent by weight are used. Usefulpromoters are also conventional and include naphthenates and alkanoatesof metals such as cobalt, lead, manganese, and calcium.

The instant unsaturated polyesters are useful in the preparation oflaminates and castings with superior qualities. Depending upon theparticular application, the selection of specific ingredients andproportions will vary. it is always necessary thatmonofunctionallyblocked isocyanurate be used to obtain resins suitablefor casting and molding. The selection of the blocking acid will affectthe hardness as well as room temperature strength and elevatedtemperature strength retention at a given level of unsaturation. Of themonocarboxylic acids which can be used to block one hydroxyl group of atris(2-hydroxyalkyl)isocyanurate, benzoic acid usually affords the bestresult in terms of rigidity and strength retention and is preferred. Useof an aliphatic blocking acid will impart greater flexibility to thepolyester.

It has been found that the use of a glycol in the manner disclosedhereinbefore, such as propylene glycol, improves the properties of theunsaturated polyesters of blocked isocyanurate. The addition of theglycol affords a more rigid polyester which has better strengthretention at elevated temperatures. For this purpose between about 10percent and 16 percent by weight of a glycol, preferably 1 l-l 3 percentby weight, is advantageously added to the polyesterification reactionmixture.

Among the improved properties which the instant unsaturated polyestershave its greater thermal stability and heat resistance. The heatstability of these polyesters, indicated by weight loss of sample in aforced-draft air oven, improves with increasing content of blockedisocyanurate in the polyester composition. For example, a polyestercontaining one mol of blocked tris(2-hydroxyethyl)isocyanurate, 1.1 molof propylene glycol and 1.0 mol of maleic anhydride lost about 1 percentof its weight at C. after 50 hours. To obtain heat resistant polyestersit is preferable to use an effective amount of at least about 0.9 molsof blocked isocyanurate per mol of dicarboxylic acid and more preferablyabout 1.1 mols. Also, the amount of modifying alcohol, such as propyleneglycol or ethylene glycol, is preferably 0.9 to 1.2 mols per mol ofdicarboxylic acid. Additional factors affecting the heat resistance ofthe unsaturated blocked isocyanurate polyesters include thea-ethylenically unsaturated polycarboxylic acid content, the nature ofthe monocarboxylic acid, and the nature of the cross-linking monomer.

As the level of a-ethylenic unsaturation increases, the heat stabilityof the polyester increases. Also, as mentioned hereinabove, diallylphthalate is a preferred cross-linking monomer to improve heatstability, and triallylisocyanurate is particularly preferred.Furthermore, use of an aromatic monocarboxylic acid as a blocking agentaffords better heat stability than does use of an aliphaticmonocarboxylic blocking acid.

The excellent heat resistance of these unsaturated polyesters rendersthem especially suitable for crosslinked castings and laminates for suchend uses as electrical applications at elevated temperature, e.g.switchgear.

With an increasing level of a-ethylenic unsaturation in the presentunsaturated polyesters, the flammability of the product is reduced toa'point where castings are self-extinguishing. For this purpose it ispreferable to have a level of a-ethylenically unsaturated acid, such asmaleic or fumaric, of at least about 14 percent by weight based on thecharge to the polyesterification reaction medium, and more preferablyabout 20 percent by weight. For example, a polyester having 14 percentby weight of maleic acid and 6.5 percent nitrogen content burns for only0.15 inches at a rate of only 0.089 inches per minute as measured by theprocedure of ASTM D-635-63 and so is classified self-extinguishing."This self-extinguishing property renders the instant polyesters usefulin applications such as building construction, military, marine, andautomotive uses.

Improved weatherability is an additional feature of the unsaturatedblocked isocyanurate polyesters of the invention. Castings and laminatesmade from these unsaturated polyesters withstand adverse weatherconditions for better than those made from materials heretoforeconsidered to have excellent weatherability. Thus,

laminates made from the instant polyesters exhibited very little fiberbloom or loss of original gloss long after other products presentlyavailable had deteriorated under conditions of high energy ultravioletradiation, high humidity, elevated temperature, and interrnittant waterspray. Furthermore, laminates made from the instant polyesters exhibitedexcellent color stability upon aging.

Methyl methacrylate is a preferred cross-linking monomer for thispurpose since it brings the refractive index of the resin closer to thatof glass. When used in a 50:50 mixture of styrene, this cross-linkingagent imparts improved weatherability to the polyesters. The amount ofcross-linking monomer to be blended with the polyester to impartimproved weather-resistance is between about 30 percent and 50 percentby weight, preferably between 35 percent and 45 percent by weight.

The isocyanurate content as well as type and level of unsaturation alsoaffects the weatherability of products made from the instant polyesters.Specifically, based on polyester charge weight, blocked isocyanuratecontent should be between about 87 percent and 64 percent andunsaturation (e.g. maleic or fumaric acids, or anhydride) content shouldbe between about 13 percent and 36 percent. Preferably, between aboutpercent and 16 percent by weight of a glycol, such as propylene glycol,will be added, thereby lowering the upper limit of isocyanurate tobetween about 77 percent and 71 percent by weight.

Other features which improve weather resistance include addedultraviolet absorbers, e.g., benzophenones and benzotriazoles, and highresin content in laminates.

Because of their ability to maintain high surface gloss, the presentpolyesters can be used advantageously in articles such as high voltageinsulators. Gloss retention is important to limit flashover or leakage,which is objectionable above a certain minimal level and which may erodethe surface and change the shape of the insulator, thereby permittingeven greater flashover. Furthermore, a weathered or rough'surface wouldcapture pollutants from the air, thus increasing conductivity andaggravating flashover. For these reasons, the improved weatherresistance of the unsaturated blocked isocyanurate polyesters makes themwell suited for this application.

The instant unsaturated polyesters may be blended into typicalanti-tracking type alkyd molding formulations for use as high voltageinsulators and other articles where anti-tracking properties areimportant. These formulations typically contain a polyester,crosslinking monomer, catalyst or initiator, stabilizer, hydratedaluminas, and the like, in accordance with techniques well known tothose skilled in the art.

Also, these polyesters can be blended into high-impact type alkydmolding compounds of the variety familiar to those skilled in the art.All these alkyd molding compounds may contain pigments and fillers wheredesirable. When the formulations of the instant unsaturated polyestersare to be fabricated into final products, they can be cured, pressuremolded, transfer molded, and injection molded by standard procedures.For example, the polyester can be cut with a cross-linking monomer andcured with 1% benzoyl peroxide (in a 50 percent tricresyl phosphatepaste) for 18 hours at 50 C., followed by 2.5 hours at l20l 25 C.

The following examples are provided to more fully illustrate the instantinvention. They are provided for illustrative purposes only and are notto be construed in any way as limiting the scope of invention which isdefined by the appended claims. In the examples, percent is by weight.

EXAMPLE I Monofunctionally-blocked Tris(2-hydroxyethyl)isocyanurateTris(2-hydroxyethyl)isocyanurate (1620.4 g., 6.21 mols) and benzoic acid(833.1 g., 6.83 mols) were charged into a 5 liter, baffled resin kettleequipped with a twin-bladed stainless steel turbine agitator,thermometer, adjustable-length nitrogen inlet tube, and steam-jacketedAllihn rectification condenser with Friedrichs condenser set fordownward distillation. The mixture was brought to 220 C. from roomtemperature in 3 hours, and held at 220 C. with a Brookstatproportionating temperature controller, under a nitrogen sparge of 2.0standard cubic feet of air per hour (SCFH) and 350 RPM agitator speed.After 1 hour 38 minutes the acid number (AN) was 25.8. The reactionmixture was then cooled to room temperature to afford statisticallydifunctional benzoate-blocked tris(2- hydroxyethyl)-isocyanurate.

The procedure was repeated wherein the benzoic acid was replaced by anequivalent amount of the following acids: pivalic, caproic andpelargonic acid.

EXAMPLE ll Polyester of Benzoate-BlockedTris(Z-hydroxyethyl)-lsocyanurate and Maleic Acid Benzoate-blockedtris(2-hydroxyethyl)isocyanurate was prepared by reacting l.l mols oftris(2-hydroxyethyl)isocyanurate with 1.2 mols of benzoic acid accordingto the procedure of Example I. Upon reaching an acid number of 26.0, thereaction was cooled to C., and 1.0 mol of maleic acid was charged intothe kettle along with hydroquinone (0.02 percent by weight based ontotal reactants charged).

The mixture was brought to 210 C. over one hour and held at 210 C. witha Brookstat proportionating temperature controller under a nitrogensparge of 1.0 SCFH and 350 RPM agitator speed. AFter one hour at 210 C.the acid number had fallen below 50, and the steam-jacketedrectification condenser was removed EXAMPLE 111 Heat Resistant CastingResin Benzoate-blocked tris(2-hydroxyethyl)isocyanurate of AN 26.1 wasprepared according to the procedure of Example I, by reacting 1931.5grams of tris( 2-hydroxyethy1)isocyanurate (7.40 mols) and 994.5 gramsof benzoic acid (8.15 mols). When the desired acid number was obtained,the reaction temperature was lowered to 150 C., and maleic anhydride(1452.0 g., 14.80 mols), propylene glycol (620.0 g., 8.15 mols), andhydroquinone (1.00 g., 0.02 weight on charge weight) were added. Thetemperature was raised from 150 C. to 210 C. over 1% hours and heldthere, using a Brookstat proportionating temperature controller.Agitator speed was maintained at around 350 RPM and N sparge rate at1.5-2.0 SCFH during the time. When the acid number had fallen below 50the overhead'was set for total take-off of volatiles, and 0.75 g. (.015wt. percent on charge) hydroquinone added. After 5 541 hours at 210 C.the product was cooled to 160 C. and dumped into tared aluminum foiltrays. The properties of the polyester were:

Yield, of theory Acid Number (AN) Hydroxyl Number (HN) Number AverageMol. Wt., M Gardner-Holt Bubble Viscosity 19.2 (mg. KOH/g. sample) 52.5(mg. KOH/g. sample) D" (50% solids in methyl cellosolve) A portion ofthe solids was dissolved in diallyl phthalate (DAP) by stirring at25-68.5 C. to give 52.7 percent diallyl phthalate content (2.8:1 allylgroup: maleic equivalence ratio). This solution (thinned viscosity Z wasmixed with 1 percent (on resin solution weight) benzoyl peroxide, as a50 percent paste in tricresyl phosphate, and poured between polyvinylalcohol filmcovered vertical steel and glass plates separated by a 1 /8inch thick Teflon spacer. The mold was heated for 18 hours at 50 C. and2% hours at l20125 C. in a forced-draft air oven to cure the resin.

The castings thus obtained were tested for thermal stability bymeasuring the weight loss as a function of time in a forced-draft airoven at 80 C. and at 240 C. The following Table illustrates heatresistance of the castir ,s.

80C. Time (Hours) 1 4 7 31 54 Wt. Loss 0.68 0.79 0.97 1.02 1.13 240C.Time (Hours) 1 3 19 27 91 Wt. Loss 7.3 12.0 32.5 37.4 50.7

EXAMPLE IV Self-Extinguishing Casting Resin The procedure of Example 111was repeated wherein 287.1 grams of tris(Z-hydroxyethyl)isocyanurate(1.10 mols) and 127.6 grams of caproic acid (1.10 mols) were reacted toafford a statistically difunctional tris(2- hydroxyethyl)isocyanurate.When the acid number of the blocked tris (2-hydroxyethyl)-isocyanuratewas 21.6, the reaction temperature was dropped to 153 C. and thefollowing materials were added: phthalic anhydride (37.0 grams, 0.25mol), maleic anhydride (73.5 grams, 0.75 mol) and hydroquinone (0.1845grams, 0.035 percent by weight of charge). The resulting polyester hadthe following properties:

Yield, of theory Acid Number (AN) Hydroxyl Number (HN) Number AverageM01. Wt., M Gardner-Holt Bubble Viscosity 92.0 18.9 (mg. KOH/g. sample)46.7 (mg. KOH/g. sample) 1 7 10 D-E (50% solids in methyl cellosolve)Styrene was added to give a resin solution containing 31 percent styrene(2.8:1 styrenezmaleic mol ratio), which was then mixed with benzoylperoxide and cured according to the procedure of Example 111.

A section of the clear casting thus obtained was subjected to theprocedure of ASTM D-635-63 and the following data were observed: BurningRate, 0.089 inches per minute; Distance Burned, 0.150 inches. Thecasting was self-extinguishing.

EXAMPLE V 97.9 20.2 (mg. KOH/g. sample) 20.2 (mg. KOl-l/g. sample) 2780F (50% solids in methyl cellosolve) B. High-Impact Type Alkyd MoldingCompound The following formulation was used to prepare a high-impacttype alkyd molding compound:

Yield, of theory Acid Number (AN) Hydroxyl Number (HN) Number AverageMol. Wt., M Gardner-Holt Bubble Viscosity Material Weight, g. Weight,

- Polyester from A 578 28.92 Diallyl Phthalate (DAP) Monomer 67 3.37 50%Benzoyl peroxide in Tricresyl Phosphate 28 1 .40 Lignicol B Stabilizer0.8 0.04 ASP- Filler 578 28.54 BaCO 98 4.91 Stearic Acid 19 0.94 622 b"Glass 618 30.88 Mapico Black Pigment 20 1.0

Total 2006.8 g

The polyester was dissolved, with agitation, in methylene chloride in a1 gallon can. Catalyst, stabilizer, monomer, and pigment were thenadded. After addition of the tiller and barium carbonate, a solution ofstearic acid in methylene chloride was added, and the slurry was rapidlystirred for about 15 minutes to obtain a uniform dispersion. The slurrywas then poured onto the glass in a Hobart mixer, and the mixture wasstirred to uniformly coat the glass with the slurry. The compound wasspread out on large boards and dried overnight to remove the solvent. Acharge of 460 g. was used to mold a 10 X 10 X /3 inch panel under Thispanel was exposed in a sunshine" carbon are The compound was spread outon a table and allowed to dry for several days.

A charge of 460 g. of the compound was compression molded to form a 10 X10 X A; inch panel under Atlas Weather-O-Meter to a cycle of 17 minutesspray 5 h ame molding Conditions used in Part B. and 143 minutes dry at130 F., and after approximate- A Slmllar c mpound was processed andmolded the 1y 2100 hours exposure it showed very slight fib r same way,with a polyester of the following relative bloom. A similar compound,wherein triallyl isocyanumolar composition:tr1s(2-hydroxyethyl)1socyanurate rate was substituted for DAP monomer,on an unsatubenZOlC acld malelc acld lsophthalic rated equivalencebasis, exhibited no fiber bloom under acid and p y glycol l. l these samonditi s, Both of these compounds exhibited no wet are A similar c u d bd on a b i idtracking after more than 3000 minutes (test ended blockedtris(2-hydroxyethyl)isocyanurate polyester f tracking) according to e Weare track rewhich had isophthalic acid substituted for phthalic an- ISlstance 185! (ASTM hydride and neopentyl glycol substituted forpropylene glycol, both on a molar basis, showed no fiber bloom EXAMPLESVI XIV after about 21000 hours exposure when both DAP and The procedureof Example 111 was repeated to l,3-butylenedimethacrylate were employedas prepare polyesters of the following composition, which monomers on anunsaturated equivalence basis. were then mixed with the indicatedcross-linking C. Anti-Tacking-Type Alkyd Molding Compound onomer toafford casting resins.

M Hydroxyl i t l ll l v l llt ll z Example Composition of polyester(mols) Acid No. No. nu Monomer pcrccnt ratio ;MA 10 PA 1.0); PG 1.1)23.2 23.2 2,420 S'IY 30.0 2.311 ;MA (1.0); PA (1.0); PG (1.1) 26. .l 26.ll 2,000 DAP 33. 6 2. 8:1 ;MA (1.0);AA (1.0); DEG (11) 10.0 32.8 2,110STY 30.0 2.11:1 MA (2.0); PG (1.1) 19. 2 52.5 1,505 S'IY/MMA 20. 0/20. 02. 0:1 ;1vu1 2.0 NIG 1.1) 20.0 44.0 1,730 SIY/MMA 200/230 3.2m .2 ;MA(1.0); PA 1.0) 24.2 24.2 2,320 DAP 20.2 3.1;1 .3); MA (2.0); PA (1.0)20.4 44.5 1,730 STY 26.6 2.8:1 ;MA 1.0 24.0 50.3 1,500 DAP 30.3 2.1011); MA (1. 24.6 50.3 1,500 STY 35.8 2.821 Plus 1% bcnzoyl peroxide (as50% paste in tricrcsyl phosphate). PA=Phthnlic anhydride; AA=Adlplcacid; NPG=Ncopcntyl glycol; No'rE.T=Tris(2-l1ydroxyethyl) isocyanurato;BA=Bcnzoic acid; STY=Styrene; MMA=Mctl1yl methacrylate; DAP=Diallylplithalati; NA=Nonan0ic acid; DEG=Di0thyl0nc glycol; MA=Maleicanhydride; PG=Propylene glycol.

The following formulation was used to prepare an EXAMPLE XVanti-tracking-type alkyl molding compound:

I A methacrylate-blocked tris(2-h drox eth l)-' 40 y y y 180 Malena]cyanurate of acid number 25.5 was prepared by chargingtris(2-hydroxyethyl)isocyanurate (130.5 g., 0.50 g xgag gg 3:; 3%; mol),methacrylic acid (43.3 g., 0.502 mol), toluene 10%| smbmzcr (185 Q03(235.0 g.), p-toluenesulfonic acid (6.3 g., 2.33 percent q 0325 M1 ontotal charge weight) and cupric acetate (0.45 g.) to Benzoyl Peroxide Inplasticizer I95 078 a one-liter resin kettle equipped with an agitator,ther- Zinc Stearate 20.5 0.32 mometer and Dean-Stark water trap with anAllihn 847 Glass, A" 412.5 16.5

Hydrated Alumina C43 0650 42.6 reflux condenser. A means for applicationof vacuum Hydrated Alumina 710 3553 14.21 was also attached. Thepressure was reduced to 400 BaCO, 1 0.3 4.4! 50 mm. Hg. and the reactiontemperature maintained at 2502 about 82.590 C. for about 15 hours.

Phthalic anhydride (148.0 g., 1.0 mol), ethylene Zinc stearate, thehydrated aluminas, and barium glycol (34.2 g., 0.55 mol) andhydroquinone (0.018 g., carbonate were charged into a 3 kg. capacitysigma- 0.035 percent on reactant charge) are added to the ketblade mixerand blended for about 3 minutes. tle. The vacuum means is removed and anadjustable Polyester, catalyst, stabilizers, monomer, and sufficientlength nitrogen inlet tube is placed on the kettle. Reacmethylenechloride were mixed together to form a tron is continued under nitrogenat ll5-120 C. until viscous solution which was added to the drys in thethe P t h anacld number of 36. sigma mixer. The mass was mixed until aputty was A Peroxide curmg agent 18 ed and the mixture formed (15-20minutes). Aftera uniform putty was obcqated on a Panel and Cured- A eaCoating is obtained, the mixing was continued for an additional 5 tamedminutes. More methylene chloride was added during We claim: this stageto replace losses due to evaporation. The solvent was found necessary tomaintain tractability dur- 1. An unsaturated polyester of a reactionmixture of ing blending due to the solid nature of the polyester. Theglass was added last and mixing was continued for about 10-15 minutesuntil all the glass was blended in.

a dihydroxy reactant containing at least about 5 percent by weight of astatistically difunctional isocyanurate alcohol of the formula:

wherein R is hydrogen, methyl or ethyl and R is the residue of ablocking acid having 1 to 12 carbon atoms and a dicarboxylic acidreactant containing a dicarboxylic acid or derivative thereof, andwherein one of said blocking acid or dicarboxylic acid containsa-ethylenic unsaturation.

2. A polyester according to claim 1 wherein R is the residue of analkanoic acid or an aromatic acid.

3. A polyester according to claim 1 wherein R is the residue of analkenoic acid.

4. A polyester according to claim 1 wherein R is hydrogen and R is analkanoic or aromatic acid.

5. A polyester according to claim 1 wherein R is hydrogen and R isphenyl.

6. A polyester according to claim 1 having an acid l 4 number below 60.

7. A polyester according to claim 1 wherein the dicarboxylic acidreactant contains maleic anhydride.

8. A polyester according to claim 1 wherein the dihydroxy reactantadditionally contains a modifying polyhydric polyol.

9. A polyester according to claim 1 wherein the dihydroxy reactantcontains at least 20 percent up to about 95 percent by weight of ablocked isocyanurate and from about 5 percent up to about percent byweight of a modifying polyhydric polyol.

10. A polyester according to claim 8 wherein the dihydroxy reactantcontains from about 10 percent to about 16 percent by weight of amodifying polyhydric polyol.

11. A resin composition comprising a polyester of claim 1, across-linking monomer and a curing agent.

12. A composition according to claim 10 wherein the cross-linkingmonomer is styrene.

13. A composition according to claim 10 wherein the cross-linkingmonomer is diallyl phthalate.

14. A composition according to claim 10 wherein the cross-linkingmonomer is methyl methacrylate.

15. A cured resin of the composition of claim 10.

2. A polyester according to claim 1 wherein R'' is the residue of analkanoic acid or an aromatic acid.
 3. A polyester according to claim 1wherein R'' is the residue of an alkenoic acid.
 4. A polyester accordingto claim 1 wherein R is hydrogen and R'' is an alkanoic or aromaticacid.
 5. A polyester according to claim 1 wherein R is hydrogen and R''is phenyl.
 6. A polyester according to claim 1 having an acid numberbelow
 60. 7. A polyester according to claim 1 wherein the dicarboxylicacid reactant contains maleic anhydride.
 8. A polyester according toclaim 1 wherein the dihydroxy reactant additionally contains a modifyingpolyhydric polyol.
 9. A polyester according to claim 1 wherein thedihydroxy reactant contains at least 20 percent up to about 95 percentby weight of a blocked isocyanurate and from about 5 percent up to about80 percent by weight of a modifying polyhydric polyol.
 10. A polyesteraccording to claim 8 wherein the dihydroxy reactant contains from about10 percent to about 16 percent by weight of a modifying polyhydricpolyol.
 11. A resin composition comprising a polyester of claim 1, across-linking monomer and a curing agent.
 12. A composition according toclaim 10 wherein the cross-linking monomer is styrene.
 13. A compositionaccording to claim 10 wherein the cross-linking monomer is diallylphthalate.
 14. A composition according to claim 10 wherein thecross-linking monomer is methyl methacrylate.
 15. A cured resin of thecomposition of claim 10.